The present invention relates to printing systems that make use of a replaceable printing component. More particularly, the present invention relates to replaceable printing components that include an electrical storage device for providing information to the printing system.
In the case where the printing system is an ink jet printing system an ink-jet printhead is frequently mounted within a carriage that is moved back and forth across a print media, such as paper. As the printhead is moved across the print media, a control system activates the printhead to deposit or eject ink droplets onto the print media to form images and text. Ink is provided to the printhead by a supply of ink that is either carried by the carriage or mounted to the printing system to not move with the carriage. For the case where the ink supply is not carried with the carriage, the ink supply can be intermittently or continuously connected to the printhead for replenishing the printhead. In either case, the replaceable printing components, such as the ink container and the printhead, require periodic replacement. The ink supply is replaced when exhausted. The printhead is replaced at the end of printhead life.
In the case where the printing system is an electrophotographic printing system the replaceable consumable is typically the electrophotographic engine frequently referred to as a toner cartridge. The toner cartridge often includes an intermediate imaging device such as a drum and an imaging material such as toner. The drum is charged using an energy source such as a scanning laser. The imaging material is attracted to the charged drum and is then transferred to print media. The replaceable consumable is either a supply of imaging material or the entire toner cartridge.
It is frequently desirable to alter printer parameters or provide information to the printer concurrently with the replacement of the replaceable printing components such as discussed in U.S. patent application Ser. No. 08/584,499 entitled "Replaceable Part With Integral Memory For Usage, Calibration And Other Data" assigned, now U.S. Pat. No. 5,699,091 filed Jan. 8, 1996, now U.S. Pat. No. 5,699,091 to the assignee of the present invention. U.S. patent application Ser. No. 08/584,499, discloses the use of a memory device, which contains parameters relating to the replaceable printing component. The installation of the replaceable printing component allows the printer to access the replaceable part parameters to insure high print quality. By incorporating the memory device into the replaceable printing component and storing replaceable part parameters in the memory device within the replaceable component the printing system can determine these parameters upon installation into the printing system. This automatic updating of printer parameters frees the user from having to update printer parameters each time a replaceable component is newly installed. Automatically updating printer parameters with replaceable printing component parameters insures high print quality. In addition, this automatic parameter updating tends to ensure the printer is not inadvertently damaged due to improper operation, such as, operating after the supply of ink is exhausted or operation with the wrong or non-compatible printer components.
It is important that the exchange of information between the printer and the replaceable printing component be accomplished in a highly reliable manner. One problem associated with the use of electrical contacts or terminals positioned on the replaceable printing component is that these electrical contacts are subject to contamination. Contamination can result from the handling that transfers contaminants such as hand oils and salts that are frequently present in human skin. This contamination may be transferred to the electrical contacts associated with the printer. Contamination also can result from leakage from the replaceable printing component that can contaminate the electrical contacts. For example, in the case of ink jet printing leakage of ink from the ink container or printhead may contaminate the electrical contacts. Inks used for ink-jet printing typically make use of solvents and surfactants that over time can result in corrosion of the electrical contacts preventing proper electrical contact between the printer and ink container. In addition, liquid contaminates can result in the shorting of these electrical contacts resulting in a faulty electrical interconnect and possibly system failure.
Another problem associated with the use of electrical contacts or terminals positioned on the outer portion of the replaceable consumable is that these contacts are subject to mechanical damage to the contacts such as scraping, denting or pealing, to name a few. This damage, if sufficient, may result in reliability problems or failures of the electrical interconnect between the printer and the replaceable consumable.
Still another problem associated with the use of electrical terminals positioned on the outer portion of the replaceable consumable is that these terminals subject the memory or storage device to electrostatic discharge (ESD). Electrostatic discharge results from the electric terminals contacting a charged surface resulting in a discharge through the storage device. This discharge can result in catastrophic failure or reduce lifetime or reliability of the storage device. Storage devices such as CMOS semiconductor devices are particularly susceptible to electrostatic discharge damage.
There is an ever present need for techniques for transferring information between a replaceable printing component and the printer which does not suffer from the above shortcomings. This technique should be reliable and result in relatively low manufacturing costs to maintain a relatively low overall cost of the printer.